Photosensitive pastes are widely used in electronic circuit fabrications to build conductors, resistors, dielectrics, or substrates. There is a need in the industry to replace the use of pastes with ceramic green tapes. Ceramic tapes are used primarily as a dielectric or insulating material for building multilayer ceramic substrates and other current tape products.
Both pastes and tapes contain components such as polymers, surfactants, plasticizers, photoreactive components, etc., which give certain pastes and tapes green properties that are necessary in their use. The organics are removed completely from the system during the process to achieve end use properties. Such organic removal is normally done by a thermal heating of the system above the highest decomposition temperature of the organic components ("burn-out" process).
As the application of the ceramic tape/paste products gets increasingly sophisticated and expands into new technology areas, there is a growing need to lower the ceiling temperature for the organic burn-out. One such need, for example, exists in the product development for the plasma display panel, one of emerging flat panel display technologies, where the window glass is used for the panel substrate and therefore the firing temperature has to be kept below the low softening temperature of the substrate glass (.about.600C).
The decomposition temperature of organics currently used in the industry for ceramic products (cellulose or acrylate polymers and monomers after polymerization) is close to the high end limit allowed for the burn-out step in a number of applications. Therefore, the polycarbonates and use of such polycarbonates, as disclosed herein, meet the need of a lower decomposition temperature which may be used in pastes and tapes.